In the general field of combat and commercial weaponry, there is a broad range of accessories available for mounting onto standard firearms in order to upgrade the capability of these weapons. Of particular interest in the context of upgrade accessories is the M16/M4 weapon system that is typically utilized in military or combat settings. Generally, the M16/M4 weapon includes a lower receiver, an upper receiver, a butt stock extending rearwardly from the upper and lower receivers and a barrel that is attached to the front of the upper receiver and extends in a forward direction. The barrel is attached to the front of the upper receiver by inserting the rear end of the barrel into a barrel-receiving receptacle at the front end of the upper receiver. Most new models of the M16/M4 weapons also include a dovetail rail interface integrally formed along the top of the upper receiver. This interface rail provides a convenient mounting point for many of the available accessories for use with the M16/M4 firearm, such as scopes, sighting devices, lasers and directed fire devices. The barrel is held in assembled relation with the upper receiver by a barrel nut that is threaded onto the outside surface of the barrel-receiving receptacle.
Numerous prior arm rail/hand guard assembly systems require permanent modification of the firearm before installation thereof. Specifically, such systems typically require destruction and removal of the original standard barrel nut and replacement with a proprietary barrel configuration. Thereafter, only the proprietary rail/hand guard system which is compatible with the proprietary barrel nut may be used with the firearm. Further, once the original standard barrel not has been removed, the firearm can not be returned to its original standard format. For this reason, systems which require modification or replacement of the standard barrel nut are undesirable.
It is also well known that when a gun is fired rapidly or extensively, the gun barrel increases in temperature, sometimes to several hundred degrees. To protect the user from injury, hand guards are often employed which cover both the barrel and the barrel nut, in addition to providing a surface on which accessories may be attached. Even so, the barrel nut itself, when in direct contact with the hand guard, may also transfer heat from the barrel to the hand guard, causing injury to the user.
It would therefore be useful to provide a modular fore-end rail assembly for use with a firearm that does not require permanent destruction of the barrel nut or other part of the firearm and which allows for the firearm to be rapidly returned to its stock configuration.
It would be further useful to provide a modular fore-end rail assembly for use with a firearm which comprises an element disposed between the barrel nut and the hand guard, in order to affect the rate of heat transfer from the barrel nut to the hand guard.
It would also be useful to provide a variety of rapidly interchangeable elements, each with its own thermal conduction properties, without requiring modification to the standard barrel nut.